1. Field of the Invention
The present invention relates to a rotary connector having a fixing pin for regulating the relative rotation of a rotating case and a stationary case.
2. Description of the Related Art
A rotary connector is used as a connector device for a flexible transmission medium which transfers electrical signals, optical signals, electric power, etc. between a rotating member and a stationary member rotating relatively to each other within a limited range of rotational number. In this rotary connector, a flexible flat cable is housed in the form of a spiral in an annular space defined by a rotating case and a stationary case which are combined for rotation. The rotating case is allowed to rotate relatively to the stationary case as the flat cable is tightened or loosened.
The rotary connector is designed so that the flat cable is oriented to a neutral position with respect to its tightening and loosening actions as it is fixed after assembly, in order to secure the same rotational number for either direction of a tightening or loosening. In mounting the rotary connector in the steering apparatus of an automobile, for example, the steering wheel is adjusted to a straight-advance position as the connector is set in position. Thus, the steering apparatus can securely enjoy proper operation.
According to conventional means for fixing the rotary connector to the neutral position, a fixing pin having retaining hooks, called snap fits, is removably mounted extending between mounting portions on the rotating and stationary cases, or a seal is pasted on both the cases.
If the fixing pin, which can be easily mounted and removed, is used as the means for fixing the rotary connector, any person can readily release the connector from fixation. Even though the rotary connector is adjusted to the neutral position with respect to its tightening and loosening actions before it is shipped, therefore, the fixation may be removed mischievously or by an accident so that the flat cable is deviated from the neutral position before the connector is mounted in a vehicle. However, this fact cannot be easily recognized from the appearance of the connector.
If the seal is used, on the other hand, a deliberate act, such as mischief, performed on the rotary connector adjusted to the neutral position can be detected from separation or fracture of the seal, so that the connector can be prevented from being wrongly mounted in the vehicle. However, the seal is liable to be separated or fractured by heat or vibration during transportation. In case of accidental or intentional separation, therefore, the rotary connector is expected to be readjusted to the neutral position. Thus, the seal is not a desirable means at all for fixing the rotary connector.